Loans, Troubled Debt Restructurings (Details) $ in Thousands		3 Months Ended				9 Months Ended
		Sep. 30, 2017 USD ($) Contract		Sep. 30, 2016 USD ($) Contract		Sep. 30, 2017 USD ($) Payment Contract Loan		Sep. 30, 2016 USD ($) Contract		Dec. 31, 2016 USD ($)
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring		$ 68,118				$ 68,118				$ 77,922
Troubled debt restructuring, specific reserve		$ 7,000				$ 7,000				9,000
Number of Consecutive Timely Payments Required | Payment						6
Loans classified as troubled debt restructurings [Abstract]
Number of contracts | Contract		4	[1]	12	[1]	26	[2]	32	[2]
Pre-modification recorded balance		$ 154	[1]	$ 759	[1]	$ 1,461	[2]	$ 3,239	[2]
Post-modification recorded balance		155	[1]	749	[1]	1,467	[2]	3,276	[2]
Increase (decrease) in allowance for loan losses		20		340		80		690
Charge offs due to troubled debt restructurings		0		20		$ 0		20
TDR that subsequently defaulted [Abstract]
Charge-offs on TDRs that subsequently defaulted				$ 0				$ 0
Past due period for modified loans						90 days
Minimum [Member]
Financing Receivable, Modifications [Line Items]
Modification of stated interest rate of loans, range of period						9 months
Modifications involving extension of maturity date, period range						1 month
Maximum [Member]
Financing Receivable, Modifications [Line Items]
Modification of stated interest rate of loans, range of period						36 months
Modification of stated interest rate of loans, range of period in certain circumstances						480 months
Modifications involving extension of maturity date, period range						60 months
Modifications involving extension of maturity date, period range in certain circumstances						230 months
Performing TDRs [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring		63,186				$ 63,186				70,286
Non-performing TDRs [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring	[3]	4,932				$ 4,932				7,636
Commercial and Industrial [Member]
Loans classified as troubled debt restructurings [Abstract]
Number of loans subsequently defaulted | Loan						6
TDR that subsequently defaulted [Abstract]
Recorded balance		160				$ 160
Increase (decrease) in allowance for loan loss due to TDRs that subsequently defaulted		20				40
Charge-offs on TDRs that subsequently defaulted		50				50
Other Loan Classes, Not Including Commercial and Industrial Loans [Member]
TDR that subsequently defaulted [Abstract]
Charge-offs on TDRs that subsequently defaulted		0				0
Commercial [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring		9,832				9,832				14,125
Commercial [Member] | Performing TDRs [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring		9,431				9,431				10,560
Commercial [Member] | Non-performing TDRs [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring	[3]	$ 401				$ 401				3,565
Commercial [Member] | Income Producing - Real Estate [Member]
Loans classified as troubled debt restructurings [Abstract]
Number of contracts | Contract		0	[1]	2	[1]	0	[2]	4	[2]
Pre-modification recorded balance		$ 0	[1]	$ 180	[1]	$ 0	[2]	$ 290	[2]
Post-modification recorded balance		$ 0	[1]	$ 180	[1]	$ 0	[2]	$ 290	[2]
Commercial [Member] | Land, Land Development and Construction - Real Estate [Member]
Loans classified as troubled debt restructurings [Abstract]
Number of contracts | Contract		0	[1]	0	[1]	0	[2]	0	[2]
Pre-modification recorded balance		$ 0	[1]	$ 0	[1]	$ 0	[2]	$ 0	[2]
Post-modification recorded balance		$ 0	[1]	$ 0	[1]	$ 0	[2]	$ 0	[2]
Commercial [Member] | Commercial and Industrial [Member]
Loans classified as troubled debt restructurings [Abstract]
Number of contracts | Contract		0	[1]	2	[1]	12	[2]	6	[2]
Pre-modification recorded balance		$ 0	[1]	$ 175	[1]	$ 786	[2]	$ 1,933	[2]
Post-modification recorded balance		$ 0	[1]	$ 158	[1]	$ 786	[2]	$ 1,916	[2]
Mortgage [Member] | 1-4 Family [Member]
Loans classified as troubled debt restructurings [Abstract]
Number of contracts | Contract		1	[1]	2	[1]	3	[2]	5	[2]
Pre-modification recorded balance		$ 93	[1]	$ 204	[1]	$ 142	[2]	$ 396	[2]
Post-modification recorded balance		$ 95	[1]	$ 207	[1]	$ 144	[2]	$ 470	[2]
Mortgage [Member] | Resort Lending [Member]
Loans classified as troubled debt restructurings [Abstract]
Number of contracts | Contract		0	[1]	0	[1]	1	[2]	1	[2]
Pre-modification recorded balance		$ 0	[1]	$ 0	[1]	$ 189	[2]	$ 116	[2]
Post-modification recorded balance		$ 0	[1]	$ 0	[1]	$ 189	[2]	$ 117	[2]
Mortgage [Member] | Home Equity - 1st Lien [Member]
Loans classified as troubled debt restructurings [Abstract]
Number of contracts | Contract		0	[1]	0	[1]	0	[2]	1	[2]
Pre-modification recorded balance		$ 0	[1]	$ 0	[1]	$ 0	[2]	$ 107	[2]
Post-modification recorded balance		$ 0	[1]	$ 0	[1]	$ 0	[2]	$ 78	[2]
Mortgage [Member] | Home Equity - 2nd Lien [Member]
Loans classified as troubled debt restructurings [Abstract]
Number of contracts | Contract		0	[1]	2	[1]	0	[2]	2	[2]
Pre-modification recorded balance		$ 0	[1]	$ 77	[1]	$ 0	[2]	$ 77	[2]
Post-modification recorded balance		$ 0	[1]	$ 78	[1]	$ 0	[2]	$ 78	[2]
Installment [Member] | Home Equity - 1st Lien [Member]
Loans classified as troubled debt restructurings [Abstract]
Number of contracts | Contract		0	[1]	2	[1]	2	[2]	6	[2]
Pre-modification recorded balance		$ 0	[1]	$ 82	[1]	$ 34	[2]	$ 141	[2]
Post-modification recorded balance		$ 0	[1]	$ 85	[1]	$ 37	[2]	$ 145	[2]
Installment [Member] | Home Equity - 2nd Lien [Member]
Loans classified as troubled debt restructurings [Abstract]
Number of contracts | Contract		2	[1]	1	[1]	7	[2]	5	[2]
Pre-modification recorded balance		$ 51	[1]	$ 7	[1]	$ 300	[2]	$ 133	[2]
Post-modification recorded balance		$ 50	[1]	$ 7	[1]	$ 301	[2]	$ 136	[2]
Installment [Member] | Boat Lending [Member]
Loans classified as troubled debt restructurings [Abstract]
Number of contracts | Contract		0	[1]	0	[1]	0	[2]	0	[2]
Pre-modification recorded balance		$ 0	[1]	$ 0	[1]	$ 0	[2]	$ 0	[2]
Post-modification recorded balance		$ 0	[1]	$ 0	[1]	$ 0	[2]	$ 0	[2]
Installment [Member] | Recreational Vehicle Lending [Member]
Loans classified as troubled debt restructurings [Abstract]
Number of contracts | Contract		0	[1]	0	[1]	0	[2]	0	[2]
Pre-modification recorded balance		$ 0	[1]	$ 0	[1]	$ 0	[2]	$ 0	[2]
Post-modification recorded balance		$ 0	[1]	$ 0	[1]	$ 0	[2]	$ 0	[2]
Installment [Member] | Other [Member]
Loans classified as troubled debt restructurings [Abstract]
Number of contracts | Contract		1	[1]	1	[1]	1	[2]	2	[2]
Pre-modification recorded balance		$ 10	[1]	$ 34	[1]	$ 10	[2]	$ 46	[2]
Post-modification recorded balance		10	[1]	$ 34	[1]	10	[2]	$ 46	[2]
Retail [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring	[4]	58,286				58,286				63,797
Retail [Member] | Performing TDRs [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring	[4]	53,755				53,755				59,726
Retail [Member] | Non-performing TDRs [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring	[3],[4],[5]	$ 4,531				$ 4,531				$ 4,071

[1] There were no purchased mortgage loans classified as troubled debt restructurings during the three month periods ended September 30, 2017 and 2016, respectively.

[2] There were no purchased mortgage loans classified as troubled debt restructurings during the nine month periods ended September 30, 2017 and 2016, respectively.

[3] Included in non-performing loans table above.

[4] Retail loans include mortgage and installment portfolio segments.

[5] Also includes loans on non-accrual at the time of modification until six payments are received on a timely basis.